The useful answer first
A dependency is more than another project name. You still need a file that matches the mod, Minecraft version and loader you are already using.
The four dependency relationships
| Relationship | Meaning | Action |
|---|---|---|
| Required | This file needs another project or version. | Install a matching release. |
| Optional | Extra integration or features are available when another project exists. | Install only if you want that integration. |
| Incompatible | This file says the combination will clash. | Do not use the conflicting combination. |
| Embedded | The dependency is packaged inside the release. | Do not add a second copy unless the creator instructs you to. |
Why project-level dependency lists are not enough
Projects change. A library can become required, optional or unnecessary between releases, and the minimum version can move too. Ask “what does this exact file need for my game version and loader?” rather than trusting one list for the whole project.
We start with the file you picked and look for library files that match the same Minecraft version and loader. A Forge library does not make a Fabric release happy, even when both files live under the same project.
Loader APIs and libraries are dependencies too
Fabric Loader and Fabric API are different components. Many Fabric mods require Fabric API in addition to the loader. Forge and NeoForge mods can similarly rely on shared libraries or APIs published as separate projects.
Do not install the newest library file blindly. Choose a release that supports the same Minecraft version and loader as the mod that requires it.
Diagnose a missing-dependency error
- 01
Record the mod id and version named in the first dependency error.
- 02
Confirm the requesting mod file matches your Minecraft version and loader.
- 03
Open the required project and filter its releases to that same combination.
- 04
Respect any minimum, maximum or exact version constraint in the error.
- 05
Check whether the dependency is required on the client, server or both.
- 06
Remove duplicate versions of the same library from the mods folder.
- 07
Restart and read the new first error; one missing library can hide the next.
Why modpacks pin files
A modpack is a set of files that worked together, not a bag of whatever is newest today. Its manifest pins them so the loader, scripts, configuration and integrations stay lined up.
Updating one mod outside the pack can add a library, remove an API or change networking. Clone the instance, update everything that file relies on, and test a client and dedicated server before rolling it out to everyone.
Straight from the source
Sources and further reading
We read the docs so you do not have to hunt for them mid-crash. For one mod, the file you picked still gets the final word.
Try it on a real mod
Pick a release and check it
Choose your game version and loader, then see whether the exact file fits your setup.